This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2002-242048, filed on Aug. 22, 2002, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a lens-barrel of a camera or the like, and especially to a lens-barrel of sliding-type zooming lens or the like and a camera system having the lens-barrel.
2. Description of the Related Art
Conventionally known is a lens-barrel of so-called double-operation type, which performs a focus operation and a zoom operation by rotationally operating different operation members.
In this lens-barrel, an automatic focus is performed when a focus operation ring does not rotate, and a manual focus is performed by rotating the focus operation ring. Further, a zoom operation is performed by rotating a zoom operation ring.
However, with such lens-barrel of double-operation type, an operator must shift his/her hand on the lens-barrel to switch between the zoom operation and the focus operation when taking a picture, since the focus operation and the zoom operation are performed by rotationally operating the different operation members. Because of this, it is impossible to switch between the zoom operation and the focus operation quickly, causing a complicated operation.
On the other hand, also conventionally known is a lens-barrel of so-called single-operation type, which has one or two operation member(s), performs zooming by sliding operation in the optical axis direction of the operation member, and performs a manual focus by the rotational operation about the optical axis.
With such lens-barrel of single-operation type, the operator does not need to shift his/her hand on the lens-barrel to switch between the zoom operation and the manual focus operation when taking a picture. Therefore, it is possible to switch between the zoom operation and the manual focus operation quickly, resulting in a simple operation.
However, with such lens-barrel of single-operation type, a hand of the operator who takes a picture is always on the operation member for performing the focus operation and the zoom operation. Therefore, there has been a problem of possibly developing an out-of-focus picture with the lens-barrel which switches from the automatic focus mode to the manual focus mode automatically by the rotation of the operation member.
That is, if the operator unintentionally rotates the operation member during the zoom operation which is the sliding operation of the operation member in the optical axis direction, it causes switching from the automatic focus mode to the manual focus mode automatically. Then, photographing is performed in such a state that the focus cannot be refocused, and thus possibly causing a problem of developing an out-of-focus picture.
It is an object of the present invention to reliably prevent unintentional switching from an automatic focus mode to a manual focus mode during a zoom operation.
According to one of the aspects of the present invention, the lens-barrel includes a photographing optical system, a zooming unit for moving a variable power lens of the photographing optical system in an optical axis direction of the photographing optical system to vary a focal length, a focusing unit for moving a focusing lens of the photographing optical system in the optical axis direction to achieve focus, a manual operation member being operated in a first direction to thereby allow the zooming unit to be operable and operated in a second direction to thereby allow the focusing unit to be operable, the second direction being different from the first direction, an automatic focus unit for driving the focusing unit to focus the photographing optical system without operating the manual operation member, a zoom operation detecting unit for detecting the operation of the manual operation member in the first direction, a focus operation detecting unit for detecting the operation of the manual operation member in the second direction, and a control unit being capable of switching a way of achieving the focus from the automatic focus unit""s operation to the manual operation member""s operation in the second direction, when detecting that the manual operation member is operated in the second direction during the automatic focus unit""s operation. The control unit does not perform the switching while the zoom operation detecting unit detects driving of the zooming unit, even when detecting the operation of the manual operation member in the second direction. That is, when the manual operation member is not operated, the control unit is in the automatic focus mode in which the focusing unit is automatically driven by the automatic focus unit. When the manual operation member is operated in the second direction, the control unit comes to be in the manual focus mode achieving focus by the operation of the manual operation member in the second direction. However, when detecting the operation of the manual operation member in the second direction during the zoom operation in which the manual operation member is being operated in the first direction, the control unit comes to be in the automatic focus mode without switching to the manual focus mode. Therefore, unintentional switching from the automatic focus mode to the manual focus mode can be reliably prevented.
According to another aspect of the present invention, the lens-barrel includes a photographing optical system, a zooming unit for moving a variable power lens of the photographing optical system in an optical axis direction of the photographing optical system to vary a focal length, a focusing unit for moving a focusing lens of the photographing optical system in the optical axis direction to achieve focus, a manual operation member being operated in a first direction to thereby allow the zooming unit to be operable and operated in a second direction to thereby allow the focusing unit to be operable, the second direction being different from the first direction, an automatic focus unit for driving the focusing unit to focus the photographing optical system without operating the manual operation member, a zoom operation detecting unit for detecting the operation of the manual operation member in the first direction, a focus operation detecting unit for detecting the operation of the manual operation member in the second direction, and a control unit being capable of switching a way of achieving the focus from the automatic focus unit""s operation to the manual operation member""s operation in the second direction, when detecting that the manual operation member is operated in the second direction during the automatic focus unit""s operation. The focus operation detecting unit can measure an operational amount of the manual operation member in the second direction, and while the zoom operation detecting unit detects driving of the zooming unit, the control unit does not perform the switching until the focus operation detecting unit determines that the operational amount of the manual operation member in the second direction has exceeded a predetermined amount. That is, while the zoom operation detecting unit detects driving of the zooming unit, the switching to the manual focus mode is not performed until the focus operation detecting unit determines that the operational amount of the manual operation member in the second direction has exceeded the predetermined amount. Therefore, as long as the operational amount of the manual operation member in the second direction does not exceed the predetermined amount, that is, as long as an operator does not operate the manual operation member intentionally, the switching to the manual focus mode does not occur. Thus, unintentional switching from the automatic focus mode to the manual focus mode can be effectively prevented.
According to another aspect of the present invention, the first direction of the manual operation member is the optical axis direction, and the second direction of the manual operation member is a direction in which the manual operation member rotates about the optical axis of the photographing optical system. The zoom operation is performed by moving the manual operation member in the optical axis direction, and the manual focus operation is performed by rotating the manual operation member. Therefore, since the operator does not need to shift his/her hand on the lens-barrel to switch between the zoom operation and the manual focus operation when taking a picture, it is possible to perform the switching quickly, resulting in simple operation.
According to another aspect of the present invention, the automatic focus unit drives the focusing unit by an ultrasonic motor which includes a stator composed of a piezoelectric element and an elastic body with its surface elliptically moving by vibrations created by the piezoelectric element, and a rotor which adjoins the stator and is moved rotationally by the vibrations of the stator. The ultrasonic motor has characteristics that it is small in size and light in weight, has no magnetism, has excellent responsiveness, and can obtain a high torque even in low-speed, thereby being capable of achieving the automatic focus immediately with high accuracy.
According to another aspect of the present invention, the focus operation detecting unit includes a printed-circuit board and brushes being pressured by the printed-circuit board to make sliding contact with a plurality of electrical conductor patterns arranged on the printed-circuit board one after another, the electrical conductor patterns being arranged on a periphery of the printed-circuit board with intervals of predetermined pitches, and the focus operation detecting unit detects the operation of the manual operation member in the second direction. That is, the operational amount of the manual operation member in the second direction is measured by having the brushes pressured and made sliding contact with the electrical conductor patterns being arranged on the periphery of the printed-circuit board with intervals of predetermined pitches. Therefore, the operational amount of the manual operation member in the second direction can be reliably measured with high accuracy.
According to another aspect of the present invention, the zoom operation detecting unit includes a printed-circuit board and brushes being pressured by the printed-circuit board to make sliding contact with a plurality of electrical conductor patterns arranged on the printed-circuit board one after another, the electrical conductor patterns being arranged on a periphery of the printed-circuit board with intervals of predetermined pitches, and the zoom operation detecting unit detects the operation of the manual operation member in the first direction. That is, the operational amount of the manual operation member in the first direction is measured by having the brushes pressured and made sliding contact with the electrical conductor patterns being arranged on the periphery of the printed-circuit board with intervals of predetermined pitches. Therefore, the operational amount of the manual operation member in the first direction can be reliably measured with high accuracy.
According to another aspect of the present invention, a camera system has a lens-barrel and a camera body to which the lens-barrel is attached. The lens-barrel includes a photographing optical system, a zooming unit for moving a variable power lens of the photographing optical system in an optical axis direction of the photographing optical system to vary a focal length, a focusing unit for moving a focusing lens of the photographing optical system in the optical axis direction to achieve focus, a manual operation member being operated in a first direction to thereby allow the zooming unit to be operable and operated in a second direction to thereby allow the focusing unit to be operable, the second direction being different from the first direction, an automatic focus unit for driving the focusing unit to focus the photographing optical system without operating the manual operation member, a zoom operation detecting unit for detecting the operation of the manual operation member in the first direction, a focus operation detecting unit for detecting the operation of the manual operation member in the second direction, and a control unit being capable of switching a way of achieving the focus from the automatic focus unit""s operation to the manual operation member""s operation in the second direction, when detecting that the manual operation member is operated in the second direction during the automatic focus unit""s operation. The control unit does not perform the switching while the zoom operation detecting unit detects driving of the zooming unit, even when detecting the operation of the manual operation member in the second direction. That is, when the manual operation member is not operated, the control unit is in the automatic focus mode in which the focusing unit is automatically driven by the automatic focus unit. When the manual operation member is operated in the second direction, the control unit comes to be in the manual focus mode achieving focus by the operation of the manual operation member in the second direction. However, when detecting the operation of the manual operation member in the second direction during the zoom operation in which the manual operation member is being operated in the first direction, the control unit comes to be in the automatic focus mode without switching to the manual focus mode. Therefore, unintentional switching from the automatic focus mode to the manual focus mode can be reliably prevented.
According to another aspect of the present invention, a camera system has a lens-barrel and a camera body to which the lens-barrel is attached. The lens-barrel includes a photographing optical system, a zooming unit for moving a variable power lens of the photographing optical system in an optical axis direction of the photographing optical system to vary a focal length, a focusing unit for moving a focusing lens of the photographing optical system in the optical axis direction to achieve focus, a manual operation member being operated in a first direction to thereby allow the zooming unit to be operable and operated in a second direction to thereby allow the focusing unit to be operable, the second direction being different from the first direction, an automatic focus unit for driving the focusing unit to focus the photographing optical system without operating the manual operation member, a zoom operation detecting unit for detecting the operation of the manual operation member in the first direction, a focus operation detecting unit for detecting the operation of the manual operation member in the second direction, and a control unit being capable of switching a way of achieving the focus from the automatic focus unit""s operation to the manual operation member""s operation in the second direction, when detecting that the manual operation member is operated in the second direction during the automatic focus unit""s operation. The focus operation detecting unit can measure an operational amount of the manual operation member in the second direction, and while the zoom operation detecting unit detects driving of the zooming unit, the control unit does not perform the switching until the focus operation detecting unit determines that the operational amount of the manual operation member in the second direction has exceeded a predetermined amount. That is, while the zoom operation detecting unit detects driving of the zooming unit, the switching to the manual focus mode is not performed until the focus operation detecting unit determines that the operational amount of the manual operation member in the second direction has exceeded the predetermined amount. Therefore, as long as the operational amount of the manual operation member in the second direction does not exceed the predetermined amount, that is, as long as the operator does not operate the manual operation member intentionally, the switching to the manual focus mode does not occur. Thus, unintentional switching from the automatic focus mode to the manual focus mode can be effectively prevented.